Deletion of the lifespan determinant p66(Shc) improves performance in a spatial memory task, decreases levels of oxidative stress markers in the hippocampus and increases levels of the neurotrophin BDNF in adult mice

p66Shc in Cardiovascular Pathology

p66Shc is a widely expressed protein that governs a variety of cardiovascular pathologies by generating, and exacerbating, pro-apoptotic ROS signals. Here, we review p66Shc’s connections to reactive oxygen species, expression, localization, and discuss p66Shc signaling and mitochondrial functions. Emphasis is placed on recent p66Shc mitochondrial function discoveries including structure/function relationships, ROS identity and regulation, mechanistic insights, and how p66Shc-cyt c interactions can influence p66Shc mitochondrial function. Based on recent findings, a new p66Shc mitochondrial function model is also put forth wherein p66Shc acts as a rheostat that can promote or antagonize apoptosis. A discussion of how the revised p66Shc model fits previous findings in p66Shc-mediated cardiovascular pathology follows.

Effects of Pueraria candollei var mirifica (Airy Shaw and Suvat.) Niyomdham on Ovariectomy-Induced Cognitive Impairment and Oxidative Stress in the Mouse Brain

The effects of the phytoestrogen-enriched plant Pueraria mirifica (PM) extract on ovari-ectomy (OVX)-induced cognitive impairment and hippocampal oxidative stress in mice were investigated. Daily treatment with PM and 17β-estradiol (E2) significantly elevated cognitive behavior as evaluated by using the Y maze test, the novel object recognition test (NORT), and the Morris water maze test (MWM), attenuated atrophic changes in the uterus and decreased serum 17β-estradiol levels. The treatments significantly ameliorated ovariectomy-induced oxidative stress in the hippocampus and serum by a decrease in malondialdehyde (MDA), an enhancement of superoxide dismutase, and catalase activity, including significantly down-regulated expression of IL-1β, IL-6 and TNF-α proinflammatory cytokines, while up-regulating expression of PI3K. The present results suggest that PM extract suppresses oxidative brain damage and dysfunctions in the hippocampal antioxidant system, including the neuroinflammatory system in OVX animals, thereby preventing OVX-induced cognitive impairment. The present results indicate that PM exerts beneficial effects on cognitive deficits for which menopause/ovariectomy have been implicated as risk factors.

Curcuma Longa, the "Golden Spice" to Counteract Neuroinflammaging and Cognitive Decline-What Have We Learned and What Needs to Be Done

Due to the global increase in lifespan, the proportion of people showing cognitive impairment is expected to grow exponentially. As target-specific drugs capable of tackling dementia are lagging behind, the focus of preclinical and clinical research has recently shifted towards natural products. Curcumin, one of the best investigated botanical constituents in the biomedical literature, has been receiving increased interest due to its unique molecular structure, which targets inflammatory and antioxidant pathways. These pathways have been shown to be critical for neurodegenerative disorders such as Alzheimer's disease and more in general for cognitive decline. Despite the substantial preclinical literature on the potential biomedical effects of curcumin, its relatively low bioavailability, poor water solubility and rapid metabolism/excretion have hampered clinical trials, resulting in mixed and inconclusive findings. In this review, we highlight current knowledge on the potential effects of this natural compound on cognition. Furthermore, we focus on new strategies to overcome current limitations in its use and improve its efficacy, with attention also on gender-driven differences.

Natural products improve healthspan in aged mice and rats: A systematic review and meta-analysis

Over the last decades a decrease in mortality has paved the way for late onset pathologies such as cardiovascular, metabolic or neurodegenerative diseases. This evidence has led many researchers to shift their focus from researching ways to extend lifespan to finding ways to increase the number of years spent in good health; "healthspan" is indeed the emerging concept of such quest for ageing without chronic or disabling diseases and dysfunctions. Regular consumption of natural products might improve healthspan, although the mechanisms of action are still poorly understood. Since preclinical studies aimed to assess the efficacy and safety of these compounds are growing, we performed a systematic review and meta-analysis on the effects of natural products on healthspan in mouse and rat models of physiological ageing. Results indicate that natural compounds show robust effects improving stress resistance and cognitive abilities. These promising data call for further studies investigating the underlying mechanisms in more depth.

The anxiolytic effect of a promising quinoline containing selenium with the contribution of the serotonergic and GABAergic pathways: Modulation of parameters associated with anxiety in mice

Recently, we demonstrated the promising anxiolytic action of 7-chloro-4-(phenylselanyl) quinoline (4-PSQ) in mice. For this reason, the objective of this study was to expand our previous findings by investigating the contribution of serotoninergic and GABAergic systems to the anxiolytic action of this compound. Pretreatment with different serotoninergic antagonists (pindolol, WAY100635 and ketanserin) blocked the anxiolytic effect caused by 4-PSQ (50 mg/kg, per oral) in the elevated plus maze (EPM) test. The contribution of the GABAergic system was investigated by pretreatment with pentylenetetrazole (a GABA_A receptor antagonist) (PTZ). 4-PSQ diminished the PTZ-induced anxiety, and did not modify the locomotor, exploratory and motor activities of mice. Later, this group of animals was euthanized and the blood was removed to determine the levels of corticosterone, and cerebral cortex and hippocampus to determine the mRNA expression levels of cAMP response element binding protein (CREB), brain derived neurotrophic factor (BDNF) and nuclear factor kappa B (NF-κB), as well as the Na⁺, K⁺ ATPase activity and reactive species (RS) levels. 4-PSQ was able to significantly reverse the increase in RS and corticosterone levels, as well as the decrease of CREB and BDNF expression in the cerebral structures and increase of NF-κB expression in the hippocampus. Finally, 4-PSQ restored the Na⁺, K⁺ ATPase activity in the cerebral structures evaluated. Here, we showed that the modulation of serotonergic and GABAergic systems, factors related to neurogenesis, oxidative status and Na⁺, K⁺ ATPase activity contributes to the anxiolytic effect of 4-PSQ and reinforces the therapeutical potential of this compound for the treatment of anxiety.

Cadmium Chloride Induces Memory Deficits and Hippocampal Damage by Activating the JNK/p66Shc/NADPH Oxidase Axis

This study investigated whether the mechanism underlying the neurotoxic effects of cadmium chloride (CdCl₂) in rats involves p⁶⁶Shc. This study comprised an initial in vivo experiment followed by an in vitro experiment. For the in vivo experiment, male rats were orally administered saline (vehicle) or CdCl₂ (0.05 mg/kg) for 30 days. Thereafter, spatial and retention memory of rats were tested and their hippocampi were used for biochemical and molecular analyses. For the in vitro experiment, control or p⁶⁶Shc-deficient hippocampal cells were treated with CdCl₂ (25 µM) in the presence or absence of SP600125, a c-Jun N-terminal kinase (JNK) inhibitor. Cadmium chloride impaired the spatial learning and retention memory of rats; depleted levels of glutathione and manganese superoxide dismutase; increased reactive oxygen species (ROS), tumor necrosis factor α, and interleukin 6; and induced nuclear factor kappa B activation. Cadmium chloride also decreased the number of pyramidal cells in the CA1 region and induced severe damage to the mitochondria and endoplasmic reticulum of cells in the hippocampi of rats. Moreover, CdCl₂ increased the total unphosphorylated p66Shc, phosphorylated (Ser³⁶) p⁶⁶Shc, phosphorylated JNK, nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, cytochrome c, and cleaved caspase-3. A dose-response increase in cell death, ROS, DNA damage, p⁶⁶Shc, and NADPH oxidase was also observed in cultured hippocampal cells treated with CdCl₂. Of note, all of these biochemical changes were attenuated by silencing p⁶⁶Shc or inhibiting JNK with SP600125. In conclusion, CdCl₂ induces hippocampal ROS generation and apoptosis by promoting the JNK-mediated activation of p⁶⁶Shc.

Sleep, brain vascular health and ageing

Sleep maintains the function of the entire body through homeostasis. Chronic sleep deprivation (CSD) is a prime health concern in the modern world. Previous reports have shown that CSD has profound negative effects on brain vasculature at both the cellular and molecular levels, and that this is a major cause of cognitive dysfunction and early vascular ageing. However, correlations among sleep deprivation (SD), brain vascular changes and ageing have barely been looked into. This review attempts to correlate the alterations in the levels of major neurotransmitters (acetylcholine, adrenaline, GABA and glutamate) and signalling molecules (Sirt1, PGC1α, FOXO, P66^shc, PARP1) in SD and changes in brain vasculature, cognitive dysfunction and early ageing. It also aims to connect SD-induced loss in the number of dendritic spines and their effects on alterations in synaptic plasticity, cognitive disabilities and early vascular ageing based on data available in scientific literature. To the best of our knowledge, this is the first article providing a pathophysiological basis to link SD to brain vascular ageing.

Maternal Obesity as a Risk Factor for Brain Development and Mental Health in the Offspring

Maternal obesity plays a key role in the health trajectory of the offspring. Although research on this topic has largely focused on the potential of this condition to increase the risk for child obesity, it is becoming more and more evident that it can also significantly impact cognitive function and mental health. The mechanisms underlying these effects are starting to be elucidated and point to the placenta as a critical organ that may mediate changes in the response to stress, immune function and oxidative stress. Long-term effects of maternal obesity may rely upon epigenetic changes in selected genes that are involved in metabolic and trophic regulations of the brain. More recent evidence also indicates the gut microbiota as a potential mediator of these effects. Overall, understanding cause-effect relationships can allow the development of preventive measures that could rely upon dietary changes in the mother and the offspring. Addressing diets appears more feasible than developing new pharmacological targets and has the potential to affect the multiple interconnected physiological pathways engaged by these complex regulations, allowing prevention of both metabolic and mental disorders.

Stem Cell Modeling of Neuroferritinopathy Reveals Iron as a Determinant of Senescence and Ferroptosis during Neuronal Aging

Neuroferritinopathy (NF) is a movement disorder caused by alterations in the L-ferritin gene that generate cytosolic free iron. NF is a unique pathophysiological model for determining the direct consequences of cell iron dysregulation. We established lines of induced pluripotent stem cells from fibroblasts from two NF patients and one isogenic control obtained by CRISPR/Cas9 technology. NF fibroblasts, neural progenitors, and neurons exhibited the presence of increased cytosolic iron, which was also detectable as: ferritin aggregates, alterations in the iron parameters, oxidative damage, and the onset of a senescence phenotype, particularly severe in the neurons. In this spontaneous senescence model, NF cells had impaired survival and died by ferroptosis. Thus, non-ferritin-bound iron is sufficient per se to cause both cell senescence and ferroptotic cell death in human fibroblasts and neurons. These results provide strong evidence supporting the primary role of iron in neuronal aging and degeneration.

p66Shc activation promotes increased oxidative phosphorylation and renders CNS cells more vulnerable to amyloid beta toxicity

A key pathological feature of Alzheimer's disease (AD) is the accumulation of the neurotoxic amyloid beta (Aβ) peptide within the brains of affected individuals. Previous studies have shown that neuronal cells selected for resistance to Aβ toxicity display a metabolic shift from mitochondrial-dependent oxidative phosphorylation (OXPHOS) to aerobic glycolysis to meet their energy needs. The Src homology/collagen (Shc) adaptor protein p66Shc is a key regulator of mitochondrial function, ROS production and aging. Moreover, increased expression and activation of p66Shc promotes a shift in the cellular metabolic state from aerobic glycolysis to OXPHOS in cancer cells. Here we evaluated the hypothesis that activation of p66Shc in CNS cells promotes both increased OXPHOS and enhanced sensitivity to Aβ toxicity. The effect of altered p66Shc expression on metabolic activity was assessed in rodent HT22 and B12 cell lines of neuronal and glial origin respectively. Overexpression of p66Shc repressed glycolytic enzyme expression and increased both mitochondrial electron transport chain activity and ROS levels in HT22 cells. The opposite effect was observed when endogenous p66Shc expression was knocked down in B12 cells. Moreover, p66Shc activation in both cell lines increased their sensitivity to Aβ toxicity. Our findings indicate that expression and activation of p66Shc renders CNS cells more sensitive to Aβ toxicity by promoting mitochondrial OXPHOS and ROS production while repressing aerobic glycolysis. Thus, p66Shc may represent a potential therapeutically relevant target for the treatment of AD.

The role of oxidative stress in anxiety disorder: cause or consequence?

Anxiety disorders are the most common mental illness in the USA affecting 18% of the population. The cause(s) of anxiety disorders is/are not completely clear, and research in the neurobiology of anxiety at the molecular level is still rather limited. Although mounting clinical and preclinical evidence now indicates that oxidative stress may be a major component of anxiety pathology, whether oxidative stress is the cause or consequence remains elusive. Studies conducted over the past few years suggest that anxiety disorders may be characterised by lowered antioxidant defences and increased oxidative damage to proteins, lipids, and nucleic acids. In particular, oxidative modifications to proteins have actually been proposed as a potential factor in the onset and progression of several psychiatric disorders, including anxiety and depressive disorders. Oxidised proteins are normally degraded by the proteasome proteolytic complex in the cell cytoplasm, nucleus, and endoplasmic reticulum. The Lon protease performs a similar protective function inside mitochondria. Impairment of the proteasome and/or the Lon protease results in the accumulation of toxic oxidised proteins in the brain, which can cause severe neuronal trauma. Recent evidence points to possible proteolytic dysfunction and accumulation of damaged, oxidised proteins as factors that may determine the appearance and severity of psychotic symptoms in mood disorders. Thus, critical interactions between oxidative stress, proteasome, and the Lon protease may provide keys to the molecular mechanisms involved in emotional regulation, and may also be of great help in designing and screening novel anxiolytics and antidepressants.

Administration of the Antioxidant N-Acetyl-Cysteine in Pregnant Mice Has Long-Term Positive Effects on Metabolic and Behavioral Endpoints of Male and Female Offspring Prenatally Exposed to a High-Fat Diet

A growing body of evidence suggests the consumption of high-fat diet (HFD) during pregnancy to model maternal obesity and the associated increase in oxidative stress (OS), might act as powerful prenatal stressors, leading to adult stress-related metabolic or behavioral disorders. We hypothesized that administration of antioxidants throughout gestation might counteract the negative effects of prenatal exposure to metabolic challenges (maternal HFD feeding during pregnancy) on the developing fetus. In this study, female C57BL/6J mice were fed HFD for 13 weeks (from 5-weeks of age until delivery) and were exposed to the N-acetyl-cysteine (NAC) antioxidant from 10-weeks of age until right before delivery. Body weight of the offspring was assessed following birth, up to weaning and at adulthood. The metabolic, neuroendocrine and emotional profile of the adult offspring was tested at 3-months of age. Prenatal HFD increased mother’s body weight and offspring’s weight at the time of weaning, when administered in conjunction with NAC. In females, NAC administration reduced high levels of leptin resulting from prenatal HFD. Prenatal NAC administration also resulted in greater glucose tolerance and insulin sensitivity while increasing adiponectin levels, as well as increasing exploratory behavior, an effect accompanied by reduced plasma corticosterone levels in response to restraint stress. Analysis of glutathione levels in the hypothalamus and in brown adipose tissue indicates that, while HFD administration to pregnant dams led to reduced levels of glutathione in the offspring, as in the male hypothalamus, NAC was able to revert this effect and to increase glutathione levels both in the periphery (Brown Adipose Tissue, both males and females) and in the central nervous system (males). Overall, results from this study indicate that the body redox milieu should be tightly regulated during fetal life and that buffering OS during pregnancy can have important long-term consequences on metabolic and behavioral endpoints.

p66Shc Inactivation Modifies RNS Production, Regulates Sirt3 Activity, and Improves Mitochondrial Homeostasis, Delaying the Aging Process in Mouse Brain

Programmed and damage aging theories have traditionally been conceived as stand-alone schools of thought. However, the p66Shc adaptor protein has demonstrated that aging-regulating genes and reactive oxygen species (ROS) are closely interconnected, since its absence modifies metabolic homeostasis by providing oxidative stress resistance and promoting longevity. p66Shc(-/-) mice are a unique opportunity to further comprehend the bidirectional relationship between redox homeostasis and the imbalance of mitochondrial biogenesis and dynamics during aging. This study shows that brain mitochondria of p66Shc(-/-) aged mice exhibit a reduced alteration of redox balance with a decrease in both ROS generation and its detoxification activity. We also demonstrate a strong link between reactive nitrogen species (RNS) and mitochondrial function, morphology, and biogenesis, where low levels of ONOO- formation present in aged p66Shc(-/-) mouse brain prevent protein nitration, delaying the loss of biological functions characteristic of the aging process. Sirt3 modulates age-associated mitochondrial biology and function via lysine deacetylation of target proteins, and we show that its regulation depends on its nitration status and is benefited by the improved NAD+/NADH ratio in aged p66Shc(-/-) brain mitochondria. Low levels of protein nitration and acetylation could cause the metabolic homeostasis maintenance observed during aging in this group, thus increasing its lifespan.

Chronic dietary ginseng extract administration ameliorates antioxidant and cholinergic systems in the brains of aged mice

Background

Black ginseng has a more potent biological activity than non-steamed ginseng. We investigated the effects of long-term intake of dietary black ginseng extract (BG) on antioxidant activity in aged mice. We also compared the effects of BG on cognitive deficits with those of white ginseng extract (WG) and red ginseng extract (RG).

Methods

Ten-month-old mice were fed an AIN-93G-based diet containing 10 g/kg (low dose, L) or 30 g/kg (high dose, H) WG powder, RG powder, or BG powder for 24 wk. We measured serum lipids, the activities of antioxidant enzymes, and malondialdehyde levels. Additionally, the protein expression levels of choline acetyltransferase and vesicular acetylcholine transporter, which are presynaptic cholinergic markers in the cortex and hippocampus of the brain, were measured by western blotting.

Results

Triglyceride levels were reduced in all the extract-treated mice, except those in the LBG group. High-density lipoprotein cholesterol levels in the HBG group were higher than those in the control group. Total cholesterol levels were reduced in the LBG group. Additionally, glucose levels in the HBG group were significantly reduced by 41.2%. There were lower levels of malondialdehyde in the LBG group than in the control group. Furthermore, glutathione reductase activity increased in the HWG group and the HRG group. The protein expression levels of choline acetyltransferase and vesicular acetylcholine transporter significantly increased in all the ginseng-treated groups.

Conclusion

The results suggest that supplementation with the tested ginseng extracts may suppress the cognitive decline associated with aging, via regulation of the cholinergic and antioxidant defense systems.

Genetic ablation of the p66Shc adaptor protein reverses cognitive deficits and improves mitochondrial function in an APP transgenic mouse model of Alzheimer's disease

The mammalian ShcA adaptor protein p66^Shc is a key regulator of mitochondrial reactive oxygen species (ROS) production and has previously been shown to mediate amyloid β (Aβ)-peptide-induced cytotoxicity in vitro. Moreover, p66^Shc is involved in mammalian longevity and lifespan determination as revealed in the p66^Shc knockout mice, which are characterized by a 30% prolonged lifespan, lower ROS levels and protection from age-related impairment of physical and cognitive performance. In this study, we hypothesized a role for p66^Shc in Aβ-induced toxicity in vivo and investigated the effects of genetic p66^Shc deletion in the PSAPP transgenic mice, an established Alzheimer's disease mouse model of β-amyloidosis. p66^Shc-ablated PSAPP mice were characterized by an improved survival and a complete rescue of Aβ-induced cognitive deficits at the age of 15 months. Importantly, these beneficial effects on survival and cognitive performance were independent of Aβ levels and amyloid plaque deposition, but were associated with improved brain mitochondrial respiration, a reversal of mitochondrial complex I dysfunction, restored adenosine triphosphate production and reduced ROS levels. The results of this study support a role for p66^Shc in Aβ-related mitochondrial dysfunction and oxidative damage in vivo, and suggest that p66^Shc ablation may be a promising novel therapeutic strategy against Aβ-induced toxicity and cognitive impairment.

Small molecule compounds alleviate anisomycin-induced oxidative stress injury in SH-SY5Y cells via downregulation of p66shc and Aβ1-42 expression

Oxidative stress and ageing are important factors contributing to the pathogenesis of Alzheimer's disease (AD), which is associated with neuronal damage and β-amyloid (Aβ) deposition. The p66shc adaptor protein is important for the regulation of oxidative stress and ageing. In the present study, SH-SY5Y human neuroblastoma cells were treated with anisomycin in order to establish a cell model of oxidative stress-induced neuronal damage. The results from quantitative polymerase chain reaction, enzyme-linked immunosorbent assay and western blotting demonstrated that anisomycin was able to stimulate the secretion of Aβ1-42 from SH-SY5Y cells and upregulate the expression levels of p66shc, which was associated with concomitant damage to SH-SY5Y cells. In addition, the protective effects of various small molecule compounds with antioxidant properties against neuronal damage were evaluated. Notably, treatment of SH-SY5Y cells with gallic acid was associated with significant downregulation of p66shc protein expression levels, reduced anisomycin-induced secretion of Aβ1-42, and increased superoxide dismutase activity and acetylcholine secretion levels. The results of the present study suggested that anisomycin is able to promote oxidative neuronal damage by inducing the secretion of Aβ1-42 from neurons and increasing the neuronal expression of p66shc, and this damage may be attenuated by treatment with gallic acid. Therefore, gallic acid and similar small molecule compounds may be considered for the alleviation of neuronal oxidative stress injury in patients with AD.

Minocycline upregulates cyclic AMP response element binding protein and brain-derived neurotrophic factor in the hippocampus of cerebral ischemia rats and improves behavioral deficits

BACKGROUND AND PURPOSE

The cAMP response element binding protein (CREB) plays an important role in the mechanism of cognitive impairment and is also pivotal in the switch from short-term to long-term memory. Brain-derived neurotrophic factor (BDNF) seems a promising avenue in the treatment of cerebral ischemia injury since this neurotrophin could stimulate structural plasticity and repair cognitive impairment. Several findings have displayed that the dysregulation of the CREB-BDNF cascade has been involved in cognitive impairment. The aim of this study was to investigate the effect of cerebral ischemia on learning and memory as well as on the levels of CREB, phosphorylated CREB (pCREB), and BDNF, and to determine the effect of minocycline on CREB, pCREB, BDNF, and behavioral functional recovery after cerebral ischemia.

METHODS

The animal model was established by permanent bilateral occlusion of both common carotid arteries. Behavior was evaluated 5 days before decapitation with Morris water maze and open-field task. Four days after permanent bilateral occlusion of both common carotid arteries, minocycline was administered by douche via the stomach for 4 weeks. CREB and pCREB were examined by Western blotting, reverse transcription polymerase chain reaction, and immunohistochemistry. BDNF was measured by immunohistochemistry and Western blotting.

RESULTS

The model rats after minocycline treatment swam shorter distances than control rats before finding the platform (P=0.0007). The number of times the platform position was crossed for sham-operation rats was more than that of the model groups in the corresponding platform location (P=0.0021). The number of times the platform position was crossed for minocycline treatment animals was significantly increased compared to the model groups in the corresponding platform position (P=0.0016). CREB, pCREB, and BDNF were downregulated after permanent bilateral occlusion of both common carotid arteries in the model group. Minocycline increased the expression of CREB, pCREB, and BDNF, and improved cognitive suffered from impairment of permanent bilateral occlusion of both common carotid arteries.

CONCLUSION

Minocycline improved cognitive impairment from cerebral ischemia via enhancing CREB, pCREB, and BDNF activity in the hippocampus.

Propofol protects against angiotensin II-induced mouse hippocampal HT22 cells apoptosis via inhibition of p66Shc mitochondrial translocation

Hippocampal neuronal oxidative stress and apoptosis have been reported to be involved in cognitive impairment, and angiotensin II could induce hippocampal oxidative stress and apoptosis. Propofol is a widely used intravenous anesthetic agent in clinical practice, and it demonstrates significant neuroprotective activities. In this study, we investigated the mechanism how propofol protected mouse hippocampal HT22 cells against angiotensin II-induced oxidative stress and apoptosis. Cell viability was evaluated with CCK8 kit. Protein expressions of active caspase 3, cytochrome c, p66(Shc), p-p66(shc)-Ser(36), protein kinase C βII (PKCβII), Pin-1 and phosphatase A2 (PP2A) were measured by Western blot. Superoxide anion (O2(.-)) accumulation was measured with the reduction of ferricytochrome c. Compared with the control group, angiotensin II up-regulated expression of PKCβII, Pin-1 and PP2A, induced p66(Shc)-Ser(36) phosphorylation, and facilitated p66(Shc) mitochondrial translocation, resulting in O2(.-) accumulation, mitochondrial cytochrome c release, caspase 3 activation, and the inhibition of cell viability. Importantly, we found propofol inhibited angiotensin II-induced PKCβII and PP2A expression and improved p66(Shc) mitochondrial translocation, O2(.-) accumulation, mitochondrial cytochrome c release, caspase 3 activation, inhibition of cell viability. On the other hand, propofol had no effects on angiotensin II-induced Pin-1 expression and p66(Shc)-Ser(36) phosphorylation. Moreover, the protective effects of propofol on angiotensin II-induced HT22 apoptosis were similar with calyculin A, an inhibitor of PP2A and CGP53353, an inhibitor of PKCβII. However, the protective effect of propofol could be reversed by FTY720, an activator of PP2A, rather than PMA, an activator of PKCβII. Our data indicated that propofol down-regulated PP2A expression, inhibiting dephosphorylation of p66(Shc)-Ser(36) and p66(Shc) mitochondrial translocation, decreasing O2(.-) accumulation, reducing mitochondrial cytochrome c release, inhibiting caspase 3 activation. By these mechanisms, it protects mouse hippocampal HT22 cells against angiotensin II-induced apoptosis.

Gender-dependent resiliency to stressful and metabolic challenges following prenatal exposure to high-fat diet in the p66(Shc-/-) mouse

Metabolic stressful challenges during susceptible time windows, such as fetal life, can have important implications for health throughout life. Deletion of the p66^Shc gene in mice leads to reduced oxidative stress (OS), resulting in a healthy and lean phenotype characterized by increased metabolic rate, resistance to high-fat diet (HFD)-induced obesity and reduced emotionality at adulthood. Here we hypothesize that p66^Shc−/− (KO) adult offspring might be protected from the detrimental effects induced by maternal HFD administered before and during pregnancy. To test such hypothesis, we fed p66^Shc+/+ (WT) and KO females with HFD for 13 weeks starting on 5 weeks of age until delivery and tested adult male and female offspring for their metabolic, neuroendocrine, and emotional profile. Prenatal diet affected stress responses and metabolic features in a gender-dependent fashion. In particular, prenatal HFD increased plasma leptin levels and decreased anxiety-like behavior in females, while increasing body weight, particularly in KO subjects. KO mice were overall characterized by metabolic resiliency, showing a blunted change in glycemia levels in response to glucose or insulin challenges. However, in p66^Shc−/− mice, prenatal HFD affected glucose tolerance response in an opposite manner in the two genders, overriding the resilience in males and exacerbating it in females. Finally, KO females were protected from the disrupting effect of prenatal HFD on neuroendocrine response. These findings indicate that prenatal HFD alters the emotional profile and metabolic functionality of the adult individual in a gender-dependent fashion and suggest that exposure to high-caloric food during fetal life is a stressful condition interfering with the developmental programming of the adult phenotype. Deletion of the p66^Shc gene attenuates such effects, acting as a protective factor.

Developmental ORIgins of Healthy and Unhealthy AgeiNg: the role of maternal obesity--introduction to DORIAN

Europe has the highest proportion of elderly people in the world. Cardiovascular disease, type 2 diabetes, sarcopenia and cognitive decline frequently coexist in the same aged individual, sharing common early risk factors and being mutually reinforcing. Among conditions which may contribute to establish early risk factors, this review focuses on maternal obesity, since the epidemic of obesity involves an ever growing number of women of reproductive age and children, calling for appropriate studies to understand the consequences of maternal obesity on the offspring's health and for developing effective measures and policies to improve people's health before their conception and birth. Though the current knowledge suggests that the long-term impact of maternal obesity on the offspring's health may be substantial, the outcomes of maternal obesity over the lifespan have not been quantified, and the molecular changes induced by maternal obesity remain poorly characterized. We hypothesize that maternal insulin resistance and reduced placental glucocorticoid catabolism, leading to oxidative stress, may damage the DNA, either in its structure (telomere shortening) or in its function (via epigenetic changes), resulting in altered gene expression/repair, disease during life, and pathological ageing. This review illustrates the background to the EU-FP7-HEALTH-DORIAN project.

Oxygen consumption and usage during physical exercise: the balance between oxidative stress and ROS-dependent adaptive signaling

The complexity of human DNA has been affected by aerobic metabolism, including endurance exercise and oxygen toxicity. Aerobic endurance exercise could play an important role in the evolution of Homo sapiens, and oxygen was not important just for survival, but it was crucial to redox-mediated adaptation. The metabolic challenge during physical exercise results in an elevated generation of reactive oxygen species (ROS) that are important modulators of muscle contraction, antioxidant protection, and oxidative damage repair, which at moderate levels generate physiological responses. Several factors of mitochondrial biogenesis, such as peroxisome proliferator-activated receptor-γ coactivator 1α (PGC-1α), mitogen-activated protein kinase, and SIRT1, are modulated by exercise-associated changes in the redox milieu. PGC-1α activation could result in decreased oxidative challenge, either by upregulation of antioxidant enzymes and/or by an increased number of mitochondria that allows lower levels of respiratory activity for the same degree of ATP generation. Endogenous thiol antioxidants glutathione and thioredoxin are modulated with high oxygen consumption and ROS generation during physical exercise, controlling cellular function through redox-sensitive signaling and protein-protein interactions. Endurance exercise-related angiogenesis, up to a significant degree, is regulated by ROS-mediated activation of hypoxia-inducible factor 1α. Moreover, the exercise-associated ROS production could be important to DNA methylation and post-translation modifications of histone residues, which create heritable adaptive conditions based on epigenetic features of chromosomes. Accumulating data indicate that exercise with moderate intensity has systemic and complex health-promoting effects, which undoubtedly involve regulation of redox homeostasis and signaling.

Comparison of α-synuclein immunoreactivity in the hippocampus between the adult and aged beagle dogs

Alpha-synuclein (α-syn), as a neuroprotein, is expressed in neural tissue, and it is related to a synaptic transmission and neuronal plasticity. In this study, we compared the distribution and immunoreactivity of α-syn and related gliosis in hippocampus between young adult (2-3 years) and aged (10-12 years) beagle dogs. In both groups, α-syn immunoreactivity was detected in neuropil of all the hippocampal sub-regions, but not in neuronal somata. In the aged hippocampus, α-syn immunoreactivity was apparently increased in mossy fibers compared to that in the adult dog. In addition, α-syn protein level was markedly increased in the aged hippocampus. On the other hand, GFAP and Iba-1 immunoreactivity in astrocytes and microglia, respectively, were increased in all the hippocampal sub-regions of the aged group compared to that in the adult group: especially, their immunoreactivity was apparently increased around mossy fibers. In addition, in this study, we could not find any expression of α-syn in astrocytes and microglia. These results indicate that α-syn immunoreactivity apparently increases in the aged hippocampus and that GFAP and Iba-1 immunoreactivity are also apparently increased at the regions with increased α-syn immunoreactivity. This increase in α-syn expression might be a feature of normal aging.

Spatial memory decline after masticatory deprivation and aging is associated with altered laminar distribution of CA1 astrocytes

Background

Chewing imbalances are associated with neurodegeneration and are risk factors for senile dementia in humans and memory deficits in experimental animals. We investigated the impact of long-term reduced mastication on spatial memory in young, mature and aged female albino Swiss mice by stereological analysis of the laminar distribution of CA1 astrocytes. A soft diet (SD) was used to reduce mastication in the experimental group, whereas the control group was fed a hard diet (HD). Assays were performed in 3-, 6- and 18-month-old SD and HD mice.

Results

Eating a SD variably affected the number of astrocytes in the CA1 hippocampal field, and SD mice performed worse on water maze memory tests than HD mice. Three-month-old mice in both groups could remember/find a hidden platform in the water maze. However, 6-month-old SD mice, but not HD mice, exhibited significant spatial memory dysfunction. Both SD and HD 18-month-old mice showed spatial memory decline. Older SD mice had astrocyte hyperplasia in the strata pyramidale and oriens compared to 6-month-old mice. Aging induced astrocyte hypoplasia at 18 months in the lacunosum-moleculare layer of HD mice.

Conclusions

Taken together, these results suggest that the impaired spatial learning and memory induced by masticatory deprivation and aging may be associated with altered astrocyte laminar distribution and number in the CA1 hippocampal field. The underlying molecular mechanisms are unknown and merit further investigation.

The p66Shc knocked out mice are short lived under natural condition

Deletion of the p66(Shc) gene results in lean and healthy mice, retards aging, and protects from aging-associated diseases, raising the question of why p66(Shc) has been selected, and what is its physiological role. We have investigated survival and reproduction of p66(Shc)-/- mice in a population living in a large outdoor enclosure for a year, subjected to food competition and exposed to winter temperatures. Under these conditions, deletion of p66(Shc) was strongly counterselected. Laboratory studies revealed that p66(Shc)-/- mice have defects in fat accumulation, thermoregulation, and reproduction, suggesting that p66(Shc) has been evolutionarily selected because of its role in energy metabolism. These findings imply that the health impact of targeting aging genes might depend on the specific energetic niche and caution should be exercised against premature conclusions regarding gene functions that have only been observed in protected laboratory conditions.

Greater resistance to inflammation at adulthood could contribute to extended life span of p66(Shc-/-) mice

Evidence is mounting that reactive oxygen species (ROS) produced because of stressful challenges could interfere with the proper functioning of the hypothalamic-pituitary-adrenal (HPA) axis, resulting in greater vulnerability to aging and neurodegeneration. Here we tested the hypothesis that p66(Shc-/-) mice, which have been described to have an extended life span and a high resistance to oxidative stress, might be less susceptible to the effects of inflammatory insults at adulthood. Although adrenocortical reactivity in response to bacterial endotoxin (lipopolysaccharide, LPS) did not differ as a function of the genotype, a hyperdrive of the HPA axis was revealed following treatment with a synthetic glucocorticoid agonist. When measuring changes in hippocampal oxidative status following LPS, only wild-type (WT) subjects showed increased levels of F(2)-isoprostanes, an index of lipid peroxidation and free radical formation. At the same time, the neurotrophin brain-derived neurotrophic factor was selectively increased in WT subjects, while levels of prostaglandin E(2) were decreased in the mutants. Overall, the greater resilience to inflammation-induced changes in the p66(Shc-/-) mutants might underlie the better health status and the longevity characterizing these mice.

Methamphetamine preconditioning alters midbrain transcriptional responses to methamphetamine-induced injury in the rat striatum

Methamphetamine (METH) is an illicit drug which is neurotoxic to the mammalian brain. Numerous studies have revealed significant decreases in dopamine and serotonin levels in the brains of animals exposed to moderate-to-large METH doses given within short intervals of time. In contrast, repeated injections of small nontoxic doses of the drug followed by a challenge with toxic METH doses afford significant protection against monoamine depletion. The present study was undertaken to test the possibility that repeated injections of the drug might be accompanied by transcriptional changes involved in rendering the nigrostriatal dopaminergic system refractory to METH toxicity. Our results confirm that METH preconditioning can provide significant protection against METH-induced striatal dopamine depletion. In addition, the presence and absence of METH preconditioning were associated with substantial differences in the identity of the genes whose expression was affected by a toxic METH challenge. Quantitative PCR confirmed METH-induced changes in genes of interest and identified additional genes that were differentially impacted by the toxic METH challenge in the presence of METH preconditioning. These genes include small heat shock 27 kD 27 protein 2 (HspB2), thyrotropin-releasing hormone (TRH), brain derived neurotrophic factor (BDNF), c-fos, and some encoding antioxidant proteins including CuZn superoxide dismutase (CuZnSOD), glutathione peroxidase (GPx)-1, and heme oxygenase-1 (Hmox-1). These observations are consistent, in part, with the transcriptional alterations reported in models of lethal ischemic injuries which are preceded by ischemic or pharmacological preconditioning. Our findings suggest that multiple molecular pathways might work in tandem to protect the nigrostriatal dopaminergic pathway against the deleterious effects of the toxic psychostimulant. Further analysis of the molecular and cellular pathways regulated by these genes should help to provide some insight into the neuroadaptive potentials of the brain when repeatedly exposed to drugs of abuse.

Decreased superoxide production in macrophages of long-lived p66Shc knock-out mice

A decrease in reactive oxygen species (ROS) production has been associated with extended life span in animal models of longevity. Mice deficient in the p66Shc gene are long-lived, and their cells are both resistant to oxidative stress and produce less ROS. Our microarray analysis of p66Shc(-/-) mouse tissues showed alterations in transcripts involved in heme and superoxide production and insulin signaling. Thus, we carried out analysis of ROS production by NADPH oxidase (PHOX) in macrophages of control and p66Shc knock-out mice. p66Shc(-/-) mice had a 40% reduction in PHOX-dependent superoxide production. To confirm whether the defect in superoxide production was a direct consequence of p66Shc deficiency, p66Shc was knocked down with siRNA in the macrophage cell line RAW264, and a 30% defect in superoxide generation was observed. The pathway of PHOX-dependent superoxide generation was investigated. PHOX protein levels were not decreased in mutant macrophages; however, the rate and extent of phosphorylation of p47phox was decreased in mutants, as was membrane translocation of the complex. Consistently, phosphorylation of protein kinase Cdelta, Akt, and ERK (the kinases responsible for phosphorylation of p47phox) was decreased. Thus, p66Shc deficiency causes a defect in activation of the PHOX complex that results in decreased superoxide production. p66Shc-deficient mice have recently been observed to be resistant to atherosclerosis and to oxidant injury in kidney and brain. Because phagocyte-derived superoxide is often a component of oxidant injury and inflammation, we suggest that the decreased superoxide production by PHOX in p66Shc-deficient mice could contribute significantly to their relative protection from oxidant injury and consequent longevity.

Lifespan extension in genetically modified mice

Major advances in aging research have been made by studying the effect of genetic modifications on the lifespan of organisms, such as yeast, invertebrates (worms and flies) and mice. Data from yeast and invertebrates have been the most plentiful because of the ease in which genetic manipulations can be made and the rapidity by which lifespan experiments can be performed. With the ultimate focus on advancing human health, testing genetic interventions in mammals is crucial, and the mouse has proven to be the mammal most amenable to this task. Lifespan studies in mice are resource intensive, requiring up to 4 years to complete. Therefore, it is critical that a set of scientifically-based criteria be followed to assure reliable results and establish statistically significant findings so other laboratories can replicate and build on the data. Only then will it be possible to confidently determine that the genetic modification extends lifespan and alters aging.

Evolution of complementary peptide systems: teneurin C-terminal-associated peptides and corticotropin-releasing factor superfamilies

In chordates, the corticotropin-releasing factor (CRF) family of peptides consists of four paralogous lineages that include CRF, urocortin/urotensin-I, urocortin 2, and urocortin 3. Related to the CRF peptide family is the diuretic hormone family found in insects. This family consists of a number of paralogous lineages within the Insecta. The teneurin C-terminal-associated peptides (TCAP) are a recently described family of peptides with evolutionary origins around the same time as the CRF family. This family consists of four independent lineages in chordates that are orthologous to peptides in the Insecta. Like CRF, the peptides are 40 or 41 amino acids in length and share about 20% sequence identity to the CRF family members. Each of the four TCAP peptides is encoded by an exon that is closely associated with the teneurin gene. Recent studies indicate that TCAP can block CRF-mediated c-fos expression in the brain and modulate CRF-mediated behaviors. Thus, the TCAP family may act, in part, to modulate the physiological actions of the CRF family.

Long-term ginsenoside administration prevents memory impairment in aged C57BL/6J mice by up-regulating the synaptic plasticity-related proteins in hippocampus

Memory impairment is considered to be one of the most prominent consequences of aging. Deterioration of memory begins in advance of old age in animals, including humans. Thus, it is extremely important to prevent memory decline for increasing healthy aging. Ginsenoside, the effective ingredient of ginseng, has been reported to have a neuron beneficial effect, but the preventive role on memory impairment and the underlying mechanisms have not been well determined. In the present study, C57BL/6J mice aged 12 months were chronically treated with ginsenoside 100mg/kg per day for 8 months. Placebo-treated aged mice, young and adult ones (4- and 8-month-old, respectively) were used as controls. The efficacious effect of ginsenoside was manifested in the amelioration of memory impairment in aged mice by Morris water maze and step-down tests. Compared with aged control group, the plasticity-related proteins including phospho-N-methyl-d-aspartate receptor1 (NMDAR1), phospho-calcium-calmodulin dependent kinase II (CaMK II), phospho-PKA catalytic beta subunit (PKA Cbeta), phospho-cAMP-response element binding protein (CREB) and brain derived neurotrophic factor (BDNF) in hippocampus significantly increased in ginsenoside treated group. These findings suggest that ginsenoside is effective on the prevention of age-related memory impairment, and the up-regulation of plasticity-related proteins in hippocampus may be one of the mechanisms.

Long-term ginsenoside consumption prevents memory loss in aged SAMP8 mice by decreasing oxidative stress and up-regulating the plasticity-related proteins in hippocampus

Ginsenoside, the effective component of ginseng, has been reported to have a neuron protective effect, but the preventive effect on Alzheimer's disease (AD) related memory loss and the underlying mechanisms have not been well determined. The senescence-accelerated mouse (SAM) is a useful model of AD-related memory impairment. In the present study, SAMP8 mice aged 4 months were chronically treated with ginsenoside (3 dose groups were given ginsenoside in drinking water for 7 months). The three groups were treated with ginsenoside 50, 100 and 200 mg/kg per day, respectively. Placebo-treated aged mice and young ones (4 months old) were used as controls. In addition, SAMR1 mice were used as "normal aging" control. The beneficial role of ginsenoside was manifested in the prevention of memory loss in aged SAMP8 mice. The optimal dose of ginsenoside is 100 or 200 mg/kg per day. In ginsenoside treated groups, the Abeta level markedly decreased in hippocampus and antioxidase level significantly increased in serum. In addition, the plasticity-related proteins in hippocampus significantly increased in the two ginsenoside treated groups. The plasticity-related proteins were checked in the present study including postsynaptic density-95 (PSD-95), phosphor-N-methyl-D-aspartate receptor 1 (p-NMDAR1), phospho-calcium-calmodulin dependent kinase II (p-CaMKII), phospho-protein kinase A Catalyticbeta subunit (p-PKA Cbeta) and protein kinase Cgamma subunit (PKCgamma), phospho-CREB (p-CREB) and brain derived neurotrophic factor (BDNF) etc. These findings suggest that the increase of antioxidation and up-regulation of plasticity-related proteins in hippocampus may be one of the mechanisms of ginsenoside on the memory loss prevention in aged SAMP8 mice.